A SIM card (full form Subscriber Identity Module or Subscriber Identification Module
SIM cards store the required information to identify the mobile device. It also contains data required for voice encryption to make listening in on calls almost impossible
Replaceable SIM cards come in four standard sizes:
• Full-size (85.6mm × 53.98mm × 0.76 mm) • Mini-SIM (25mm x 15mm x 0.76mm) • Micro-SIM (15mm x 12mm x 0.76mm) • Nano-SIM (12.3mm × 8.8mm × 0.67mm)
The eSIM or Embedded SIM comes in one size:
• eSIM (6mm x 5mm x <1mm) Non Removable
SIM Card Types There are two types of SIM card namely;
GSM:
GSM technology stands for Global System for Mobiles and its foundation can be credited to Bell Laboratories in 1970. It uses a circuit-switched system and divides each 200 kHz signal into 8 25 kHz time slots and operates in 900 MHz, 800 MHz, and 1.8GHz bands. It uses a narrow band transmission technique- basically Time Division Access Multiplexing. The data transfer rates vary from 64kbps to 120kbps.
CDMA:
CDMA means code division multiple access which explains about communication channel principle that employs spread-spectrum technology and a special coding scheme which are time-division multiplexing scheme and frequency division multiplexing scheme.
Parts and Functions of a Prepaid SIM
A SIM card has many parts whereby each has its own purpose. Here are some of the common parts and functions of each.
• RST(Reset) • VCC(Power Supply) • CLK(Clock) • VPP(Voltage Programming Power) • D+ and D- (you can choose for USB pad) • GND(Ground) • SIM Data I/O Pin
Functions of SIM Cards
Identification Authentication Store Numbers Overseas Connectivity
